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Page 379 of 977 Results 3781 - 3790 of 9762

Zhong Ruilin, Lee Sungjun, Wang Jian
RESEARCH ON DETECTING THE CENTER OF A WEIGHT

The centre of the weight need to be measured to correct the difference between centers of the test weight and the reference weight for high precise mass measurement, and a device is developed to locate the centre of the weight which includes a balance, a bridge and a supporting pole. A measuring method was proposed in [1]. A revised method is discussed in this paper and the effectiveness of the method is shown by measurements.

Dirk Röske
A GERMAN CALIBRATION GUIDELINE FOR TORQUE WRENCH CALIBRATION DEVICES REVISED

Torque wrenches are commonly used measuring instruments in many applications. They are calibrated on torque wrench calibration devices. In Germany, at least in the accredited laboratories, the latter are calibrated using precision torque transfer wrenches and applying the corresponding DKD calibration guideline. This guideline was recently revised. The main new ideas and modifications will be presented in this paper.

Jian Wang, Xiaoping Ren, Cai Changing, Nan Yang
RESEARCH ON UNCERTAINTY EVALUATION FOR MATRIX METHOD OF MASS MEASUREMENT FROM 500 µg TO 50 µg

Subdivision comparisons of mass measurement are usually used in the mass dissemination for class E1 and E2 mass standards from 1 kg to 1 mg or from 1 kg to 50 kg. Many equations of mass measurement are included in the subdivision comparisons. It is not easy to calculate values of true mass or conventional mass and the budget the uncertainty of subdivision comparisons by hand or Microsoft Excel software. Matrix calculations used in the subdivision comparisons of mass measurement are very convenient to get the true mass value or conventional mass value of every weight compared. Due to some matrixes used in the calculations, it is difficult to obtain directly the uncertainty budget of matrix method. Matrix method with uncertainty budget for measuring mass from 500 µg to 50 µg is proposed in the paper. Automatic mass comparator a5 is used to measure mass of microgram weights by matrix method of subdivision comparisons. All equations of subdivision comparisons are converted into expression of matrix. Another method for evaluating uncertainty of matrix equations that is Monte Carlo method in the paper is introduced in order to validate the calculation of uncertainty budget by means of matrix method. The values and uncertainties with respect to sets of microgram weights are calculated by programs self-developed under Mathcad software.

Xiaoping Ren, Jian Wang, Changqing Cai, Qingxiong Ren
SURFACE ANALYTICAL MODEL AND DESIGN METHOD OF MASS STANDARD BASED ON SELF ADAPTIVE ALGORITHM

Surface analytical model is presented to observe the adsorption. Mass standards with special shapes are difficult to design due to complex parameters. Method based on self-adaptive algorithm is given out to help designing the best sorption artefacts. This algorithm helps to design best shape of cylinder-weight and stack-weight that are with same volume and different surface area.

Thierry Rabault, Philippe Averlant, Frédéric Boineau
NUMERICAL MODELING OF HYSTERISIS APPLIED ON FORCE TRANSDUCER

When we need to calibrate a force transducer, we usually refer to ISO 376. This standard considers hysteresis as an error included into the uncertainty budget. The objective of this paper is to provide laboratories with tools to estimate the hysteresis. The measurements procedure, the methodology to extract the hysteresis while empowering the zero drift and non-linearity of the calibrated transducer, the modelling and the correction of its effect are proposed.

Omar J. Purata, José de la O., Elvia Funes
GEOMETRIC MEASUREMENT OF THE VOLUME OF OIML CLASSES E AND F WEIGHTS WITHOUT SURFACE CONTACT

A noncontact test method for the volume determination of weights from (1 to 1 000) g is described. The method uses an optical comparator to size cylindrical weights, and allows to compute the volume of the weight according to OIML R 111-1 Method E. The volume values obtained for the weights were compared against hydrostatic weighing volume results for reference. The volume relative uncertainty levels reached with the optical comparator are small enough for calibration operations of even OIML Class E2 weights.

Yon-Kyu Park, Min-Seok Kim, Kwang-Pyo Kim, Jin-Seok Jang, Jeong-Tae Lee, Ho-Young Lee, Dae-Im Kang
MANUFACTURING AND INSTALLATION OF A HIGH CAPACITY DEADWEIGHT FORCE MACHINE

A deadweight force standard machine is a mechanical structure that generates force by subjecting deadweights to the local gravitational field. Korea Research Institute of Standards and Science (KRISS) maintains several deadweight force machines for national force standards. KRISS is developing a 1 MN deadweight force standard machine. The project is scheduled to be finished in 2015. This paper describes the concept and structure of the force machine. The manufacturing and installation of the force machine are also described in this paper.

Feng-yu Yang, Sheau-shi Pan, Kuang-Yih Tsuei
THE TEMPERATURE CHANGE DURING MEASUREMENT VIA MASS COMPARATOR WITH AUTOMATIC LOAD ALTERNATOR

We changed a new 10-kg mass comparator with automatic load alternator at CMS (Center for Measurement Standards) last year to replace the older one which was out of function. During installation, the temperature issue comes out to affect the measurement results under the same environment of laboratory as usual. In this paper, we will discuss the abnormal phenomenon caused by the thermal effect.

Seif. M. Osman, R. Kumme, H. M. El-Hakeem, F. Löffler, Ebtisam H. Hasan, R. M. Rashad, F. Kouta
FORCE TRANSDUCER WITH DIFFERENT CAPACITIES

Force transducers are usually used by national and accredited laboratories to calibrate force generated systems. Laboratories own several load cells to carry out calibrations, this forms an over cost for purchasing several load cells. One way to solve this problem is introducing a force transducer with different capacities. This article summarizes the achievements of proposing an economical force transducer with three different capacities works in compression mode.

Koji Ogushi, Sebastian Baumgarten, Dirk Röske
ANOTHER APPROACH ANALYZING THE CROSSTALK MATRIX FOR A PRECISE FORCE-TORQUE TRANSDUCER

A new multi-component facility for force and torque, which can simultaneously realize precise axial force (Fz) and torsional moment (torque, Mz), is being developed in PTB. Moreover, precise two-axis measuring devices (force-torque transducers) as transfer standards must be also developed for the establishment of the measurement traceability of screw testing machines. Authors have calibrated a new-developed force-torque transducer in each direction of force and torque, separately. The crosstalk matrixes have been obtained by ordinal way, where the normal square-inverse matrix (2 by 2) was used. In this paper, authors tried to obtain the crosstalk matrix by means of another approach, pseudo-inverse matrix, where the data was used as many as possible (2 by 18 or 2 by 26), and the useful crosstalk matrix could be determined in one value.

Page 379 of 977 Results 3781 - 3790 of 9762